Without knowing the tags you are using for your images, I can only assume either the pictures were uploaded into the wrong directory...or you have the tag wrong. Whatever folder you FTP into, you need to make sure the tag points to that folder. Example:
<img src="logo1.JPG"> would be my tag if the picture named logo1 was in the same directory as my index page. You would change it to point to a different folder if your picture isn't in the same directory as the index. Say your picture was FTP'd to a folder called "pics", then you would change the tag to <img src="pics/logo1.JPG"> or you could also give the whole URL to the picture instead <img src="www.yourpage/pictures/logo1.JPG"> Or something like that.
Check out some of the sites listed above for HTML help. There is a lot available online if you do a search, too.
Or please post the tags you are using, so maybe we can help more.